Gaseous discharge lamp



Aug. 16, 1966 G. STONE 3,267,319

GASEOUS DISCHARGE LAMP Filed NOV. 19. 1963 FIG. 2

FIG. 3

United States Patent 3,267,319 GASEOUS DISCHARGE LAMP Gerald Stone, Syosset, N.Y., assignor to Hazeltine Research Inc., a corporation of Illinois Filed Nov. 19, 1963, Ser. No. 324,712 4 Claims. (Cl. 313-188) The present invention relates in general to gaseous discharge lamps, and more particularly to such lamps which exhibit improved luminance characteristics.

Prior gaseous discharge lamps, such as the well known type NE2, suffer from two major deficiencies. These are insuflicient light output and apparent flicker, the latter of which is caused when the glow discharge occurs at a diiferent place on the cathode each time the lamp is activated, or fired.

It is therefore an object of the present invention to provide new and improved gaseous discharge lamps which are not beset by the disadvantages and limitations mentioned above.

It is another object of the present invention to provide new and improved gaseous discharge lamps wherein the effective luminance area is greatly enlarged in comparison with prior such devices.

It is still another object of the present invention to provide new and improved gaseous discharge lamps which utilize a novel cathode structure to increase the effective light output of the lamps.

In accordance with the present invention a gaseous discharge lamp comprises an envelope, and a glow producing gas contained within the envelope. The gaseous discharge lamp also includes a glow sustaining structure also contained within the envelope, having an anode and at least one transparent cathode, the cathode having a transparent electrically-conductive coating. The gaseous discharge lamp finally includes feedthrough terminals for making electrical connection to the glow sustaining structure contained within the envelope.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing:

FIGURE 1 is an illustration of one form of gaseous discharge lamp which is constructed in accordance with the present invention;

FIG. 2 illustrates another form of gaseous discharge lamp which is constructed in accordance with the present invention, and

FIG. 3 is an isometric drawing of the gaseous discharge lamp of FIG. 1.

There is shown in FIG. 1 a gaseous discharge lamp constructed in accordance with the present invention. As shown, the lamp of FIG. 1 includes an envelope, which in the present example is a conventional glass lamp envelope 10, but which may be any suitable lamp envelope. The lamp of FIG. 1 also includes a glow producing gas contained within the envelope 10. A suitable glow producing gas which may be used in the lamp of FIG. 1 is conventional neon gas.

In addition, the lamp of FIG. 1 includes a glow sustaining structure also contained within the envelope '10, having an anode 13 and at least one transparent cathode 14, the cathode 14 having a transparent electrically-conductive coating 15. In the present example, anode 1 3 is of conventional metal construction while cathode 14 is constructed of conventional glass which is coated on all sides with a transparent electrically conductive coating 15. A

suitable commercially available substance which may be 3,267,319 Patented August 16, 1966 used for the coating 15 is type EC coating produced by Corn-ing Glass Company.

The lamp of FIG. 1 finally includes feedthrough terminals 11 and 12 for making electrical connection to the glow sustaining structure contained within the envelope 10. The feedthrough terminals 11 and 12 serve both to structurally support and electrically feed anode 1 3 and cathode 14, respectively. For that purpose, anode 13 and cathode 14 are mechanically and electrically bonded to the electrical conductors 1'1 and '12 respectively.

The lamp of FIG. 1 shows, for illustrative purposes only, anode 13 and cathode 14 as being flat and disk-like in shape. This example is not meant to impose any limitations on the structural configuration of glow discharge lamps constructed in accordance with the present invention. Using the teachings of the present invention, many different lamp configurations will be obvious to persons skilled in the art.

In operation, a DC. voltage source is connected to the feedthrough terminals 11 and 12, usually through a current limiting resistor. At low current levels, a glow discharge will be evidenced at the minimum spacing gap between anode 13 and cathode 14. If the current is gradually increased, however, a point will be reached where the glow discharge covers the entire coated surfaces of cathode 14. In other words, both the surface facing anode 1'3 and the opposite surface of cathode 14 will be covered by the glow. Since cathode 14 is transparent and coating 15 is likewise transparent, the glow on the underside of cathode 14 will be visible when viewed through its upper surface, together with the glow present on the upper surface. Thus the luminance is additive and serves to approximately double the elfective light output of the glow discharge tube.

A modification of the glow discharge lamp described above is shown in FIG. 2. In this example additional cathodes 16, 17 and 18 have been added in spatial alignment with the original cathode 14. Since the additional cathodes are also transparent, and since a glow is present on each surface of the additional cathodes, the effective light output of the modified glow discharge lamp of FIG. 2 will be approximately N times the light output of the lamp of FIG. 1, where N is the number of cathodes used. There will be some degradation of the luminance from lower cathodes, such as cathode 14, for example, as it passes through the additional cathodes 16, 17 and 18. This is due to the fact that the cathodes and their accompanying conductive coatings are not perfectly transparent.

An added feature of the present invention is that the source of luminance is an area source rather than a point source, as is the case in conventional glow discharge lamps. This feature has particular utility when, for example, the glow discharge lamp is used to provide background luminance for alpha-numeric characters in a display.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A gaseous discharge lamp, comprising:

an envelope;

a glow producing gas contained within said envelope;

at least two feedthrough terminals for providing electrical connections into said envelope;

an anode connected to one of said feedthrough terminals;

and a plurality of transparent cathodes connected to 3 4 another of said feedthrough terminals and aligned to each other in a stack, one behind another, with the one behind the other so that said cathodes glow intended viewing direction approximately perpendicular simultaneously when energized and the glow from to the first cathode of the stack. distant cathodes is visible through the nearest cathode; whereby when the lamp is energized, increased lumi- 5 References Cit d b h E i nance is obtained from the additive effect of the plurality of glowing cathodes. UNITED TES PATENTS 2. A gaseous discharge lamp in accordance with claim 2,512 359 1950 smith 313 .2Q2 X 1, wherein said cathodes are constructed of transparent 3 075 119 1/1963 Botden 3 3 1 9 5 dielectric material covered by a transparent, electrically 10 3,127,535 3/1964 Westerheim 313 1O9'5 conductive coating.

3. A gaseous discharge lamp in accordance with claim FOREIGN PATENTS 2 wherein said cathodes are planar in order to provide 908,697 10/1962 Great m additional glow producing area, and said conductive coating covers both sides of the cathode so that substan- 15 D AVID J GALVIN Primary Examine). tially the whole area on both sides glows.

4. A gaseous discharge lamp in accordance with claim ROBERT SEGAL, GEORGE N. WESTBY, 1, wherein said cathodes are planar and arranged parallel S. SCHLOSSER, Assistant Examiners. 

1. A GASEOUS DISCHARGE LAMP, COMPRISING: AN ENVELOPE; A GLOW PRODUCING GAS CONTAINED WITHIN SAID ENVELOPE; AT LEAST TWO FEEDTHROUGH TERMINALS FOR PROVIDING ELECTRICAL CONNECTIONS INTO SAID ENVELOPE; AN ANODE CONNECTED TO ONE OF SAID FEEDTHROUGH TERMINALS; AND A PLURALITY OF TRANSPARENT CATHODES CONNECTED TO ANOTHER OF SAID FEEDTHROUGH TERMINALS AND ALIGNED ONE BEHIND THE OTHER SO THAT SAID CATHODES GLOW SIMULTANEOUSLY WHEN ENERGIZED AND THE GLOW FROM DISTANT CATHODES IS VISIBLE THROUGH THE NEAREST CATHODE; WHEREBY WHEN THE LAMP IS ENERGIZED, INCREASED LUMINANCE IS OBTAINED FROM THE ADDITIVE EFFECT OF THE PLURALITY OF GLOWING CATHODES. 